Metronelec MENISCO ST88 NEO, User Manual, Page: 40 / 83

USER MANUAL
SOLDERABILITY TESTER
METRONELEC
V2.0 – 10/2021
6 Avenue Eiffel - 78420 Carrières-sur-Seine
Tél : 01 30 15 20 00
Web : http://www.metronelec.com| Mail : contact@metronelec.com Page 40 sur 83
Example curve of “zero crossing time”
Crossing time is 0.38 s between the curve and the X axis level (continuous blue line)
Print Pass Fail Data : You can print, only if you select different curves in merge, a table of
values with the different curves result and obtain a pass/fail result following the criteria :
Ta(s) : Crossing time with the buoyancy line, often fixed to 0,7 s or 0,59s for Mil spec.
Tb(s) : Crossing time with the zero line, often fixed to 1,0 s.
TF1(s) / F1(mN) : You can define a pass fail limit point with a minimum level F1 expressed
in mN (could be negative for partial wetting, ex pcb) at a certain time TF1(s). The curve
should pass over this level F1 at the time TF1. (Use in IEC 60-2-69)
TF2(s) / F2(mN) : same than above to define a second point (TF2, F2), we tolerate often a
dewetting between F1 and F2 of 20%.
T2/3Fmax : Crossing time with the calculated value of the 2/3 of the maximum force,
should be usually less than 1.0 s. The maximum force is extracted from the geometry of the
component and the hypothesis of a “full wetting” with a wetting angle supposed to be at
zero.
Dew : Dewetting is expressed as a limit percentage between the maximum force and the
minimum force (minimum known after this maximum), so the dewetting is equal to (Fmax –